By popular demand - here is how you handle when new players join the game mid-campaign.

There are 2 different ways, the first one is to enable client autospawning, the other is to spawn one in manually.

==Auto Spawning==
1) As server host (or with privelages) press "T" to open chat
2) enter 'mcm client autospawn true' (without the ' )
3) you should se the setting being updated in the chat window. New users should spawn with their preferred character now

==Manual Spawn==
1) As server host (or with privelages) press "T" to open chat
2) enter 'mcm clientlist' to open a window that contains all unique players connected to your server
3) copy the first number of the pair, ie. "> 1234 < | 0123456789"... We'll refer to it as id
4) enter 'mcm spawn {ID}' : mcm spawn 1234
5) A new character should now appear for your client to take control over

You can also enter 'mcm' or 'mcm help' to open up the in-game help menu that gives you some short descriptions on what chat commands you can use. Enjoy!